The Biological Basis of Language

1. The Biological Basis of Language The Vocal Tract The Brain

2. Question from the readings. • Why didn’t the British experts understand that there was a difference?

4. Evolution • Evolution does not have a direction or purpose. • There is no reason that the evolution of the vocal tract and the brain took the forms that they did. • Things could be otherwise.

5. Stephen Jay GouldWonderful life : the Burgess Shale and the nature of history. New York : W.W. Norton, c1989.The mismeasure of man. NewYork : Norton, c1981.

6. The Vocal Tract • The source-filter theory • What are formants • How is the vocal tract an illustration of the source-filter theory (what is the source? What is the filter? • How are the vowels /a/, /i/, /u/ produced? • What about consonants? • The segmentation of speech • The organs of speech

7. The source-filter theory • What are formants? • How is the vocal tract an illustration of the source-filter theory (what is the source? What is the filter?

8. Spectogram

9. The Filter • The filter is a simple question of fitting a wave in a tube. • A formant is the frequency of wave that is reinforced by the filter. • Length is the primary consideration • Open and closed tubes function differently. • The first formant of schwa is the waveform that fits in a 17 cm open tube. Calculating Schwa 

10. Calculating Schwa • Frequency: number of cycles (highs and lows per second). • How long is a given sound wave? • How fast can sound travel in a second • 33,500cm/sec • How long is a 500 hertz sound? • 33,500 divided by 500 = 67 cm • What is the open tube filter for a 67cm wave. • 67 divided by 4 = 17 cm. • What’s so great about 17 cm? Length of human vocal tract.

11. Schematic of a i u

12. Formant 1 versus Formant 2

13. The Vocal Tract

14. Human versus Chimp Vocal Tract

16. Consonantscon + sonant

17. Conclusion • The source-filter theory explains the operation of the vocal tract. • The larynx serves as the source • The pharynx and oral cavity and nasal cavity serve as the filters. • The articulation of the vowels i a u involve gross movements. • Consonants hang on the vowels.

18. The Brain • Brief history of the science and the brain • The modular principle What is it • What are the modular areas of the brain most relevant to the brain? • Broca’s area • Wernicke’s area • The functioning of language • Implications for Evolution

19. Brief history of the science and the brain • Done in the context of Eurocentrism • Presumption of Superiority • larger brains = more intelligence • adjust for size: change to percentage of body weight. • Women have a higher ration of brain to body weight than men. • Hypothesized that women had a lot of air between the brain and the skull.

20. The modular principle • Understood in the 2nd half of the 19th century. • Forgotten in the 1st half of the 20th century. • rediscovered in the 2nd half of the 20th century. • Forgotten in the 1st half of the 21st century??? • What is it? • Areas of the brain are specialized for different functions.

21. Face Recognition

23. What are the areas of the brain most relevant to the brain?

25. The Brain and Language

27. Conclusion • Both the Brain and the Vocal Tract have evolved to facilitate adult human language. • This raises many questions. When did it happen? • Are their behavioral equivalents? • Next lecture.